diff --git a/README.md b/README.md
index 6ab83f5..8ec3a18 100644
--- a/README.md
+++ b/README.md
@@ -92,6 +92,7 @@ RadiationD-v1.1(CAJOE):
 
 ## ToDo
 * https://tinker.yeoman.com.au/2016/05/29/running-nodemcu-on-a-battery-esp8266-low-power-consumption-revisited/
+* deep_sleep (connect D0 to RST)
 * https://hackaday.com/2014/10/25/use-a-cheap-pin-diode-as-a-geiger-counter/ (opengeiger.de/elektronik.html)
 * Solar power